Republicans — and many Democrats — have seized on the botched Oct. 1 rollout of many parts of the Patient Protection and Affordable Care Act, commonly called Obamacare, as evidence of the entire law’s failure. And Mr. Cuccinelli, who was the first attorney general in the country to sue over the reform package, is no exception.

“This is a referendum on Obamacare,” Mr. Cuccinelli told supporters Tuesday. “Why would we double down on failure?”

Members of both parties have been furious with the rollout of the law, but the partial government shutdown, which disproportionately affected defense-heavy Virginia, dominated the headlines for the first half of October. Accordingly, the problems associated with the health care law do not appear to be resonating — at least not yet — with the broader Virginia electorate.

For example, 60 percent of likely voters in a Politico/PPP/Harper poll taken in early October rated the rollout of Obamacare as “fair” or “poor,” and yet Mr. McAuliffe led Mr. Cuccinelli in the same poll by 9 points, 44 percent to 35 percent.

Mr. Cuccinelli also blasted the news that Mr. Obama will campaign with Mr. McAuliffe on Sunday in Arlington, accusing the Obama administration of knowingly misleading the public when officials said people would be able to stay on existing health plans.

“In other words, President Obama was selling the public on the most significant law in a generation under false pretenses,” Mr. Cuccinelli said

The White House said Tuesday that Mr. Obama didn’t mislead the public when he promised everyone could keep their plan under Obamacare.

“The president was clear about a basic fact,” said White House press secretary Jay Carney, who added that Mr. Obama was making the promise only for people who held a policy when the law was enacted in 2010. He said those people are being “grandfathered” under the law.

“Clearly, it should have been caveated with, ‘Assuming you have a policy that, in fact, does do what the bill is designed to do,’ ” Mr. Hoyer said.

Mr. McAuliffe has made the portion of the law that allows states to expand their Medicaid rolls using federal subsidies a key portion of his economic plan, while Mr. Cuccinelli says the federal government simply cannot be trusted to come up with the money to pay for it and that Mr. McAuliffe’s projections are overly optimistic.

Under the law, up to 400,000 low-income Virginians could gain health coverage with the expansion. The federal government foots 100 percent of the expansion costs through 2017, and the subsidy gradually winds down to 90 percent.

“We must act,” Mr. McAuliffe said at a recent campaign stop. “That is Virginia money coming back to Virginia and it will create 30,000 new jobs.”

But Mr. Cuccinelli, who appeared with Louisiana Gov. Bobby Jindal after stumping with Sen. Rand Paul, Kentucky Republican, on Monday, lambasted the law Tuesday.

“Make no mistake, this is a fundamental and critical difference in the race for governor,” he said. “Virginians must be warned, Obamacare will negatively affect you, your friends and even your family. On Election Day, the vote you cast will have a huge impact on whether we have a governor who protects the rule of law, fights for job creators and puts the best interests of the commonwealth first, or a governor who perpetuates a lie that hurts the very people he aspires to govern for the sole purpose of growing the reach and power of government.”